Field of the Invention
The present invention relates to a three-dimensional image pickup lens system, and more particularly, to a three-dimensional image pickup lens system configured to control an optical axis by using an image stabilization unit, and an image pickup system including the three-dimensional image pickup lens system.
Description of the Related Art
Hitherto, there is known an image pickup system for three-dimensional imaging by using multiple image pickup apparatuses, each of which can foe used as a standalone lens apparatus. A pair of image pickup apparatuses used for three-dimensional imaging is configured to be driven simultaneously so that optical conditions are always identical, which vary in accordance with a state or a position of a control target such as zoom, focus, and stop. In addition, a three-dimensional effect is adjusted by adjusting a convergence length at which the optical axes of the respective image pickup apparatuses cross in shooting, and a base length as a distance between the image pickup apparatuses. Images taken by the three-dimensional imaging in this way are each combined as an image for a left eye and an image for a right eye.
As a method for controlling an angle of convergence, there are proposed a method of rotating the entire image pickup apparatus so as to change an optical axis direction for changing the angle of convergence, and a method of displacing an optical element such as a mirror or a prism for bending a light beam so as to change the optical axis direction for changing the angle of convergence. However, in either method, a structure of the image pickup apparatus becomes large. In addition, because the image pickup apparatus becomes a dedicated one for the three-dimensional imaging, it has no versatility and has poor usability.
In order to solve this problem, for example, Japanese Patent Application Laid-Open No. 2010-103895 discloses a method of controlling the angle of convergence by using an optical element (hereinafter referred to as a shift lens) mounted for image stabilization that moves in a plane perpendicular to the optical axis. In addition, there is disclosed a method of adjusting the angle of convergence and correcting image blur by adding a movement amount of the shift lens for controlling the angle of convergence to a movement amount of the shift lens for image stabilization for driving.
In addition, in an imaging method called panning photography, the above-mentioned movement amount of the shift lens for image stabilization is integrated when a panning operation is performed. When it is detected that an integrated value has exceeded a maximum correction angle, panning determination is performed for determining that not a fluctuation to be subjected to the image stabilization has occurred but the panning operation has been performed, and the shift lens is returned to a predetermined position. However, in a state where the convergence length is set in three-dimensional imaging, because the maximum correction angle is different between the right and left lenses, a parallax displacement is generated between the right and left lenses.
In order to solve this problem, for example, Japanese Patent Application Laid-Open No. 2011-017929 discloses a method of returning a mechanism for image stabilization to an optical axis center ox each lens when the panning operation, is detected, which enables to prevent the above-mentioned parallax displacement.
However, in the above-mentioned conventional technologies disclosed in Japanese Patent Application Laid-Open No. 2010-103895 and Japanese Patent Application Laid-Open No. 2011-017929, because the image stabilization mechanism is returned to the optical axis center regardless of the set convergence length, a parallax amount is different between during normal photography and during panning photography.
For instance, if the panning operation is performed while a subject is being photographed with a certain parallax amount, the convergence length is returned to the optical axis center only during the panning operation, and hence the three-dimensional effect is different. In this case, an unnatural image is taken during the panning operation. In particular, the image is unusable in photographing a moving image.